Value on Electrocompaniet

Hello there..Newbie here...I've been asked to sell some audio EQ for a buddy but we have no idea of the value of a 
Electrocompaniet amp & preamp..there's no model #'s & based on a YouTube video I watched it's exactly these units but no info..he got these in the early to mid 70's & I think in the very early production units..any help would be appreciate..he also has a HK Citation Sixteen power amp..B&O Beogram 4002 TT w/cartridge...Yamaha PX 2 TT w/cartridge.
Thanks, Jack